The present invention is related generally to a method and apparatus for preventing aliasing in an electronic still camera. In particular, the present invention is related to a method and apparatus for preventing aliasing that employs mechanical dithering in place of a birefringent antialiasing filter used in conventional electronic still cameras.
Advances in the art of electronic imaging have led to the implementation of solid-state image sensors, for example charge coupled devices (CCD imagers), in electronic still image cameras. While such cameras have been proven technically feasible, conventional electronic still image cameras that produce high quality images remain out of the reach of the average consumer due to their prohibitive expense. One significant cost element associated with the production of a high quality electronic still camera is the necessity of incorporating a birefringent antialiasing filter in the camera. The birefringent antialiasing filter is used to spread out or slightly "blur" the image presented to the image sensor in order to limit the spatial frequencies at the image sensor to avoid aliasing. Birefringent filters, in addition to their expense, take up a significant amount of space and light, thereby limiting the sensitivity and increasing the size of any electronic still camera in which they are employed.
In view of the above, it would be desirable to develop a method and apparatus to prevent aliasing in electronic still cameras without using a birefringent filter. The elimination of the birefringent filter would lower the cost, decrease the size, and improve the sensitivity of an electronic still camera. Accordingly, it is an object of the invention to provide a method and apparatus for preventing aliasing that employs mechanical dithering in order to overcome the problems associated with the use of birefringent filters in electronic still cameras.